Image on the left is the PCV port
The PCV port on my LS3 manifold does not hold vacuum. The tube (see above) is 2 pieces that some how are joined together but not sealed, is this by design or intentional. It would seem to me that this is a potential vacuum leak. I’ve attached a vacuum pump to the port on the outside and plugged the tube inside the manifold and it does not hold vacuum. Any thoughts?

 

If the leak is inside the manifold it shouldn't matter. Does it appear to be leaking on the outside?

 

That’s a fair question. The way that the port is fastened is odd. It appears to be 2 pieces snapped together, but I can’t figure out how. The outside is a cap like fitting on the side of the manifold and the tube is inserted through the inside wall, but I don’t know if they connect to each other inside the cavity. I agree that if the “leak” were internal it would not be an issue, but if the outer cap is not sealed then it would cause a vacuum leak. Is there some kind of internal baffling inside the manifold at this location?